Various LED signal assemblies are employed today with great practical effect. In the automotive industry, many vehicles utilize LED-based lighting assemblies, taking advantage of their much lower energy usage as compared to other light sources, including halogen- and incandescent-based systems. One problem associated with LEDs is that they tend to produce highly directional light. The light emanating from conventional LED-based vehicular lighting assemblies often has low uniformity and hot spots. Consequently, conventional LED-based lighting assemblies have a significant drawback when used in vehicle applications requiring high uniformity—i.e., signal lamps.
Certain vehicular signal applications, e.g., daytime running lights (DRLs), require high intensity with high uniformity. Conventional approaches for achieving high uniformity with LED sources have employed specular and non-specular reflector elements, coatings and layers within the assemblies. While these approaches can improve uniformity, they often lead to significant light loss through scattering and other loss mechanisms that lead to a loss in light intensity.
In contrast, other conventional LED-based approaches can, in certain cases, achieve high intensity through minimal or no use of reflecting elements. As LEDs produce highly directional light patterns, these conventional approaches generally result in assemblies that suffer from a “spotty” appearance. Other conventional LED-based lighting approaches have resulted in some assemblies that can produce lighting patterns with moderate intensity and uniformity, but only in assemblies with linear shapes and small widths (e.g., <12 mm).
Accordingly, there is a need for LED-based vehicular signal assemblies that exhibit a high degree of light uniformity, light intensity and design flexibility.